GRAFCET Quiz

Question 1

How is the initial step drawn?

Accepted Answer

initstep

Answer

rechteck

Answer

step

Answer

transition

Question 2

How is the AND operator written in a transition condition?

Accepted Answer

·

Answer

+

Answer

≥1

Answer

!

Question 3

How do you check whether step 5 is active?

Accepted Answer

X5

Answer

S5

Answer

T5

Answer

B5

Question 4

What is GRAFCET used for?

Accepted Answer

Describing sequences independently of any vendor

Answer

Calculating signal propagation times

Answer

Programming one particular PLC brand

Answer

Wiring control cabinets

Question 5

How is a normal step drawn?

Accepted Answer

step

Answer

actionsym

Answer

initstep

Answer

transition

Question 6

Which element does this symbol represent?

Accepted Answer

A transition

Answer

A step

Answer

A link

Answer

An action

Question 7

What applies to the order of steps and transitions?

Accepted Answer

They always alternate

Answer

Two steps may follow one another

Answer

Two transitions may follow one another

Answer

The order is arbitrary

Question 8

How is the OR operator written in a transition condition?

Accepted Answer

+

Answer

&

Answer

!

Answer

·

Question 9

In which direction does a GRAFCET run by default?

Accepted Answer

From top to bottom

Answer

The direction can be chosen freely

Answer

From bottom to top

Answer

From left to right

Question 10

What is a continuous action?

Accepted Answer

It acts as long as its step is active

Answer

It stays set permanently

Answer

It only starts after a fixed time

Answer

It moves the sequence to the next step

Question 11

What characterises a stored action?

Accepted Answer

Its value is kept after the step

Answer

It is reset in every cycle

Answer

It only acts while the step is active

Answer

It only starts after a delay

Question 12

How do you write an on-delay of 15 s referring to step 2 as a transition condition?

Accepted Answer

15s/X2

Answer

15s·X2

Answer

T15/X2

Answer

X2:15s

Question 13

What does ↑SJ4 mean in a transition condition?

Accepted Answer

Rising edge of SJ4

Answer

Falling edge of SJ4

Answer

SJ4 permanently TRUE

Answer

Negation of SJ4

Question 14

How are value comparisons written in a transition condition?

Accepted Answer

In square brackets, e.g. [C1>C2]

Answer

In quotation marks " "

Answer

In round brackets ( )

Answer

In curly brackets { }

Question 15

How do you recognise a parallel branch?

Accepted Answer

By the double horizontal line

Answer

By a separate transition for each sub-sequence

Answer

By the single horizontal line

Answer

By the double vertical lines

Question 16

What does the transition condition 5s/SJ1/4s mean?

Accepted Answer

TRUE 5 s after pressing, FALSE 4 s after releasing

Answer

TRUE 4 s after pressing, FALSE 5 s after releasing

Answer

SJ1 must be pressed for 5 s and released for 4 s

Answer

5 s on, 4 s off, repeated periodically

Question 17

What characterises a delayed action?

Accepted Answer

It only becomes effective after a set time

Answer

It ends after a set time

Answer

It only acts at the moment of the step change

Answer

It keeps its value permanently

Question 18

In which order are several actions of one step carried out?

Accepted Answer

They act at the same time

Answer

From bottom to top

Answer

One after another in random order

Answer

From top to bottom

Question 19

What does the expression SJ1·(BG2+SJ3) mean?

Accepted Answer

SJ1 AND (NOT BG2 OR SJ3)

Answer

NOT (SJ1 AND BG2 AND SJ3)

Answer

SJ1 AND BG2 AND SJ3

Answer

SJ1 OR (BG2 AND SJ3)

Question 20

What does an assignment condition on a continuous action do?

Accepted Answer

The action only acts when the step is active and the condition is met

Answer

The action acts as soon as the condition is met, even without an active step

Answer

The condition delays the start of the action

Answer

The condition sets how long the action acts

Question 21

An output is driven continuously in step 3 and set by a stored action in step 5. What applies?

Accepted Answer

Not allowed — both at once is forbidden

Answer

The continuous one is ignored

Answer

The two assignments add up

Answer

The stored assignment takes precedence

Question 22

A stored action is linked to the event “on deactivation”. When is its value assigned?

Accepted Answer

At the moment the step becomes inactive

Answer

At the moment the step becomes active

Answer

Permanently, while the step is inactive

Answer

Only when the following step becomes active

Question 23

In this alternative branch both transition conditions are met at the same time. Which steps become active?

Accepted Answer

Step 2 and step 3

Answer

Only step 2

Answer

One branch chosen at random

Answer

None — the sequence stops

Question 24

When does the transition at the junction of a parallel branch fire?

Accepted Answer

When all last steps are active and its condition is met

Answer

As soon as its condition is met

Answer

When the majority of sub-sequences have finished

Answer

As soon as the first sub-sequence reaches its last step

Question 25

When is a macro-step considered complete, so that the following transition may fire?

Accepted Answer

When its output step is active

Answer

As soon as any step inside it is active

Answer

As soon as the macro-step becomes active

Answer

After a set time

Question 26

An enclosing step is deactivated while steps inside its enclosure are still active. What happens?

Accepted Answer

All steps of the enclosure are deactivated

Answer

The enclosure runs on to its end

Answer

The enclosure keeps its state for next time

Answer

The enclosing step cannot be deactivated this way

Question 27

A forcing order acts on another partial GRAFCET. What does it do there?

Accepted Answer

It puts that GRAFCET into a defined situation and holds it there

Answer

It calls that GRAFCET like a subroutine and waits for it to finish

Answer

It advances that GRAFCET by exactly one situation

Answer

It changes that GRAFCET’s transition conditions

Question 28

Starting point: only initial step 1 is active. Then SJ1 is pressed, after which BG2 becomes TRUE; BG4 stays FALSE. Which steps are active now?

Accepted Answer

Step 3 and step 4

Answer

Step 3 and step 5

Answer

Only step 3

Answer

Step 2 and step 4

Question 29

Which kind of action does this picture show?

Accepted Answer

A time-limited action

Answer

A stored action

Answer

A delayed action

Answer

An action with an assignment condition

Question 30

Step 4 is active. At the same moment one transition that deactivates step 4 fires and another one that activates it. What applies?

Accepted Answer

Step 4 stays active

Answer

Step 4 is deactivated

Answer

Step 4 is briefly deactivated and immediately reactivated

Answer

The state is undefined

GRAFCET Quiz

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